The invention relates to the formation of the running surface of skis, especially cross-country skis with or without a guide groove running in the longitudinal direction of the ski and a profiling arranged in the middle longitudinal region of the ski.
Running surface profiling for the improvement of the climbing effect of skis has long since been known. The various basic forms of the profiling are related to each other in one or more of their systematic arrangements. With the various profile forms one attempts to find a compromise between good climbing and good gliding characteristics. AT-PS 364,726 describes accordingly an embodiment which is characterized by flat rectangular surfaces arranged obliquely with respect to the snow upper surface in lateral or longitudinal directions of the ski with a constant spacing. For the sake of good climbing characteristics, in this embodiment due to the shaping and arrangement of the gliding surface, one will sacrifice good gliding characteristic.
Another possibility, which attempts to increase the climbing effect by a special structuring of the profiling, is described in EP 001557 and DE GM 8004825.
Both of these patent applications describe embodiments in which the height of the profiling is larger in the step-in region when compared with the remaining regions.
Regarding such embodiments one may say that the climbing characteristics are not influenced essentially by the magnitude of the grade, however, they are defined substantially by the force influence exerted onto the snow upper surface, at which upper surface of the snow becomes sheared off. The snow resistance to shearing off is dependent on the present snow type.
DE-OS 2755395 makes an attempt, on the other hand, to attain a good gliding characteristic by a special structuring of the gliding surface of the "scales". The arched basic shape of the scales will lead to the formation of force components which are oblique to the running direction when in the climbing phase of skiing. The force components cause an untimely shearing off of the upper surface of the snow and, thereby, the climbing effect of the profile becomes substantially reduced.
In contrast to the so far described embodiments of climbing aids DE-OS 2627887 and DE-OS 2852513 describe a different approach. These applications describe an arrangement of climbing aids arranged only on the inner side of the ski. The outer sides are in both laid-open applications formed for good gliding. With these so arranged climbing aids a good climbing effect can be attained, however, with such a running surface structuring an appropriate running style is necessary. The climbing effect of such structured climbing zone will not increase without wax being applied onto the smooth cover in the middle region in order that good climbing characteristics could be obtained.
Other embodiments, such as known from AT-PS 182997, as well as from DE-AS 2265524, attempt to substantially increase the gliding speed by non-uniform distribution of the profiling on the running surface of the ski.
In AT-PS 182997 such profiling is in the form of parallel grooves running along the longitudinal edges of the ski. Such an embodiment is characterized by a squeaking noise occurring during the gliding, which in turn will lead to an increased loss of gliding ability due to friction.
In DE-AS 2265524 the object is to suppress such "squeaking" stemming from the above arrangement.
Such object is proposed to be solved by a non-harmonic, special group-arrangement of rows, wherein the rows are systematically offset with respect to each other.
Also in such an embodiment the traveling noises cannot be completely eliminated with the help of the group-formation.
It is an object of the invention to provide a new running surface profiling which combines an optimum gliding and climbing characteristic.
The technical drawbacks of the known running surface profiling arrangements are caused in that the previously developed profile forms insufficiently consider the special requirements of the different snow types, the special loadings of the ski in the push-off and gliding phase, as well as the details of the process during the sticking and gliding of the profiling with respect to the snow, as well as the same during the transition phase sticking/gliding/sticking.